Several publications of the European Spatial Planning Observation Network (ESPON) suggest that one should be aiming at a polycentric urban system, albeit one which does not unambiguously display properties of territorial development (Vandermotten 2003). Focusing on concentration processes and implications of urban policies, the article draws attention to those regional processes (topographic) and urban networks (topologic) destined to play the double role of catalyst and diffuser of innovations in a diversified European territory. It is argued that various spatial scales and a range of different perceptions of polycentrism be taken into consideration. It is felt that only through the articulation of these differences will the relevant processes and networks be able to function optimally within a context where the interrelations of urban governance are adapted to each territory.